PubMed Health⌕ Search

Biomedical subjects

D T Osuga

Publications and source records attributed to D T Osuga.

At least 37 records · Page 2Linked to original sources
PubMed1978

Cooperative functioning between antifreeze glycoproteins.

Antifreeze glycoproteins from polar fish bloods are a mixture of closely related components which differ structurally by size and by the presence of proline in the smaller components. Although the smaller components containing proline exist in higher amounts than do the larger ones, their presence puzzled investigators because they had very weak antifreeze activity. A very important function for these smaller components has now been found. These smaller antifreeze glycoproteins (10 to 25 mg/ml) have now been tested as mixtures with the larger active antifreeze glycoproteins (2 to 4 mg/ml) and a very large (2- to 8-fold) potentiation of antifreeze activity has been observed. There appears to be a cooperative functioning between the larger and smaller components.

Animals↗
PubMed1976

Penguin evolution: protein comparisons demonstrate phylogenetic relationship to flying aquatic birds.

Quantitative immunological comparisons of three avian proteins, transferrin, ovalbumin, and penalbumin, indicate that penguins are phylogenetically most closely related to loons, albatrosses, herons, and grebes. These data support the theory that the ancestors of penguins were flying oceanic birds and that flightlessness in penguins has evolved independently from flightlessness in ratites.

Amino Acid Sequence↗
PubMed1976

Evolution of flightless land birds on southern continents: transferrin comparison shows monophyletic origin of ratites.

A biochemical approach was used to study the evolution of ratite birds, i.e., the ostriches, rheas, cassowaries, emus, and kiwis. Quantitative immunological comparison of transferrin from ratites, tinamous, and other flying birds indicates that all the ratites and tinamous are allied phylogenetically and that they are of monophyletic origin relative to other birds. To explain the current geographic distribution of ratites and the magnitude of the transferrin distances, it is supposed that the ancestors of these flightless birds walked across land bridges between the southern continents during Cretaceous times.

Amino Acid Sequence↗
PubMed1975

Antifreeze glycoproteins from an Antarctic fish. Quasi-elastic light scattering studies of the hydrodynamic conformations of antifreeze glycoproteins.

A quasi-elastic light-scattering technique was used to study the hydrodynamic conformations of antifreeze glycoproteins from an Antarctic fish. Antifreeze glycoprotein is composed of repeating units of Ala-Ala-Thr, with each threonine O-linked to a disaccharide, and it exists as several polymers of different numbers of this repeating unit. Molecular weights of the two major active polymers are 10,500 and 17,500 by such methods as centrifugation and osmotic pressure, but smaller than 20 by freezing-point depression. Translational diffusion coefficients at 20 degrees were 8.35 times 10-7 cm2 s-1 and 6.15 times 10-7 cm2 s-1 for the M-r-10,500 and 17,500 polymers, respectively. Measurements at -0.2 degrees in the presence of ice crystals did not indicate any conformational changes that might be related to the lowering of the freezing temperature. Lowering the temperature of these glycoprotein solutions close to temperatures of freezing caused a decrease in the effective hydrodynamic radius of both active and inactive glycoprotein components.

Animals↗
PubMed1975

Synthesis of immobilized flavin derivatives and their use in purification of chicken egg-white ovoflavoprotein.

Affinity adsorbents for flavoproteins were prepared by the covalent attachment of polyacrylamide and agarose to flavin derivatives linked through position N(3) of the flavin nucleus. 3-Carboxymethyl-FMN covalently linked to aminoalkyl substituted agarose was successfully used for the separation and purification of the apo form of the ovoflavoprotein from chicken egg white. High yields and high purities were achieved by two different isolation procedures employing the affinity adsorbent.

Acrylamides↗